Posts in Running Injuries
Is Lack Of Mobility Or Flexibility A Factor In My Running Injury?
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Lower extremity stiffness (“leg stiffness”) describes the resistance the joints and muscles in your lower body will have to movement when your foot contacts the ground during running. Think of your leg as a spring; the more tightly coiled spring will be stiffer, the more loosely coiled will be more deformable. A stiffer leg is associated with less joint movement (less mobility) and increased loads to bones and cartilage whereas a less stiff leg is associated with increased joint motion/mobility and relies more heavily on active muscle contraction to dissipate forces when your foot hits the ground.

 Leg stiffness may be one of many variables that contribute to running related injuries. A recent study of 92 runners {Goodwin:2019bk} identified 4 variables that may allow us to more easily predict leg stiffness with clinical measures versus technical laboratory analysis. Less mobility in the ankle joint, hip and big toe joint along with increased BMI are associated with greater leg stiffness. What is the clinical significance of this for our Boulder runners? For runners suffering from knee pain or stress fractures, reducing leg stiffness by improving the mobility of hip, ankle and foot may reduce joint loading. Conversely, in runners with soft tissue injuries such as Achilles or tibialis posterior tendinopathy, increasing leg stiffness with targeted strengthening exercises to improved stability and control of the joints of the lower extremity may be an important component of rehabilitation.

Contact your physical therapy experts at Mend to learn more about how your mobility may contribute to running injury.

Does Running Gait Retraining Translate To Running Outside The Lab?
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Researchers and clinicians continue to explore interventions to reduce the significant numbers of running related injuries. These injuries, mainly overuse in nature, often cause a loss in training time and are found among both novice and experienced runners. In addition to strength training, gait retraining has shown promise in reducing the forces placed across the lower body during running. Simple strategies such as reducing step length (heel to mid foot strike) and landing softer (reducing vertical forces) can quickly reduce forces during gait. In addition, providing runners with real time feed back through simple video analysis and verbal cuing accelerates utilization of these new running strategies. Few research articles have examined the retention rate and transfer of learning between laboratory running gait retraining and a runner’s outdoor training, but a new study shows old running habits may die harder than originally thought.

Zhang and colleagues examined runners’ gait mechanics under various conditions including overground running, treadmill running, as well as, running inclines and declines (Gait Posture. 2019). Each runner’s lower body forces were measured in a biomechanics laboratory during their preferred running gait. Based off this analysis, runners were then provided with 8 sessions of gait retraining with real time feedback (soften your foot strike) to reduce forces across the lower body. Runners were then reassessed to determine if the gait retraining transferred to an outside environment. Consistent with prior research, the majority of runners were able to reduce lower body forces during gait retraining in the laboratory. Outside of the gait retraining, they were able to reduce their overall forces during overground and treadmill running, but peak forces were not reduced during overground running. Not surprisingly, this study highlights the difficulty of changing a movement pattern like running. Consistent, deliberate practice with the principles learned during gait retraining is required to create an automatic process with athletes.

Reducing Impact Forces In Runners
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In our previous blogs, we have described interventions designed to reduce the high rates of running related injuries. To date, our best Physical Therapy interventions include controlling training volume, concurrent strength training, and gait retraining. In our Boulder Physical Therapy practice we aim to reduce peak loading forces at foot strike in our runners. This can be achieved by increasing a runner’s forward lean (from the ankles) and stride length to reduce braking forces at the foot and ankle, as well as, reducing vertical oscillation in the flight phase of running. A recent article reviewed the use of real time biofeedback to reduce these braking forces in runners.

Napier and colleagues in the Journal of Orthopedic and Sports Physical Therapy utilized biofeedback in healthy, female runners with high rates of peak braking forces (2018). Each participant was provided with an 8 session gait retraining program aimed to increase step frequency and reduce step length. Basic cuing, such as “land softer”, can be used in this population to reduce the braking forces and in turn conserve energy for forward propulsion. Authors reported significantly reduced peak braking forces after the gait retraining sessions. In addition, these gait changes have been previously associated with increased running economy and performance.

Click Here to schedule your next running gait analysis with the experts at MEND

What Is A Safe Weekly Running Progression?
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Running remains one of the most popular forms of aerobic exercise due to its’ effectiveness and minimal equipment costs and entry fees. The majority of runners will sustain a running related injury at some point in their careers limiting their ability to train or compete. Training errors, increases in a runner’s volume (frequency, duration, terrain, intensity) too quickly over time, often contribute to the development of an overuse injury. Increasing running volume without adequate recovery prevents body tissues from positively adapting to the stress of exercise. A recent study documents what percentage increases in running volume are most associated with injury.

Damsted and colleagues in the Journal of Sports Physical Therapy studied 261 healthy runners over a 14 week period as they trained for an upcoming 1/2 marathon race (2018). 22% of the runners sustained a running related injury over the 14 week study period. Authors examined participants’ running volume increases and found those who increased their running volume > 20% per week sustained significantly more injures than those increasing their volume < 20% per week.

What is the best way to reduce loading forces in runners?
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In our previous blog posts we have discussed the variety of interventions available to reduce the high injury rates seen among both novice and experienced runners.  Many of these interventions are designed to reduce the loading forces across the lower body at foot strike and push off.  In our Boulder Physical Therapy practice we commonly utilize strength training, patient education, and running gait retraining.  No consensus has been reached on the an ideal running form for all individuals, but each runner can improve their gait efficiency and injury risk through analysis and form correction.  We often find simple cues such as "land softer" are most effective at improving a runner's gait.  With runners, like most athletes, complex and multiple cues only lead to "paralysis by analysis".  Most often these cues are designed to improve step frequency (cadence) or vertical oscillation.  A new study provides insight into which cue may be most effective.

Adams and colleagues analyzed healthy runners under 3 running conditions: self selected running gait, cuing to increase step frequency, and cuing to reduce vertical oscillation (International J Sports PT. 2018).  Data on vertical loading, ground reaction forces, and braking impulse during each condition were analyzed in a biomechanics lab.  Although both the vertical oscillation and step frequency groups demonstrated improved loading measurements compared to the baseline group greater improvements were seen among the runners aiming to reduce their vertical oscillations. 

These findings are consistent with prior research indicating runners with high vertical oscillation rates (picture greater up and down movements with each stride) not only are more inefficient but also have greater rates of lower body loading and injury risk. 

Click Here to schedule your running gait analysis with the experts at MEND

 

Should I add a lift in my running shoe to improve my symptoms?
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One of the greatest misconceptions in the treatment of musculoskeletal injuries is using interventions to create symmetry in the body between right and left sides.  Asymmetry is often the norm vs. the exception but we function very well in life and sport with these asymmetries.  Small asymmetries should be accepted while larger asymmetries should be examined and treated on an individual basis.   A previous article in the NY Times highlighted the amazing performances of Usain Bolt despite having a significant leg length difference and resulting asymmetrical running gait. 

Patient's often come into our Boulder Physical Therapy practice with heel lifts based on a previous clinician's assessment and resulting intervention for a "short leg".  Side Note: We will leave the ridiculousness of SI and pelvic asymmetries or functional leg length discrepancies for another post.  There are two main errors with this reasoning first and foremost all clinical tests have significant false positives and negatives limiting their ability to find a truly short leg.  Second, static measurements, including leg alignment, have not been shown to significantly impact running injuries.  The majority of us have small differences in leg length but how much do these differences impact running injuries?

A recent study in the International Journal of Sports Physical Therapy both described the incidence of leg leg differences and examined the impact of these differences on running injuries (Rauh et al. 2018).  Authors screened 322 high school cross country athletes for leg leg differences and then followed them to determine if these differences increased the risk of lower body injury during the upcoming season.  The authors found 1 in 5 runners had a significant difference in leg length, but these differences were not associated with future injury risk.  One exception was found in athletes with a leg leg discrepancy of > 1.5 cm who were 7 times more likely to experience an injury than an athlete without a significant leg length difference. 

This study highlights and supports our clinical practice of removing more lifts than we put into a runner's shoes.  Small differences should be accepted and left alone while large differences, > 2 cm, should be lifted on an individual basis.